gboolean gdk_events_get_angle ( GdkEvent* event1, GdkEvent* event2, gdouble* angle )
If both events contain X/Y information, this function will return
and return in
angle the relative angle from
event2. The rotation
direction for positive angles is from the positive X axis towards the positive
The data is owned by the caller of the function.
Return location for the relative angle between both events.
The argument will be set by the function.